It is well known that poor indoor air quality can be harmful to health. The inhabitants of one of the earliest large settlements of mankind were apparently already affected by this problem: In the houses of Çatalhöyük in today’s Turkey, the indoor air was heavily polluted with harmful fine dust due to smoke and poor ventilation, according to an experimental study. This was probably one of the causes of the known health problems of the inhabitants of the Stone Age settlement, the scientists say.
The site of Çatalhöyük is a special hotspot of archeology, because it provides insights into the beginning of a development that still shapes the world today: It is one of the first larger settlements whose livelihood was agriculture. The place thus represents, as it were, an archetype of today’s urban structures. At the height of development around 9000 years ago, it is estimated that up to 8000 people lived in Çatalhöyük. Earlier studies have already provided indications that this settlement density was already associated with typical urban problems: there are traces of special health problems, violence and environmental problems.
According to the archaeological findings, the settlement consisted of adobe buildings that were up to 25 square meters in size. A typical house had a stove and a fireplace under an opening in the roof. There, wood and dung from domestic animals were burned for heating and cooking. It was already known that this caused layers of soot on the walls of the room, which were therefore apparently regularly re-plastered white. Studies have shown that burning biofuels can have significant negative health effects. But to what extent did this apply to the conditions in Çatalhöyük’s rooms?
Experimental archeology
Scientists working with Lisa-Marie Shillito from Newcastle University pursued this question through experimental archeology. To this end, they carried out experiments in a replica of a Çatalhöyük house, which is intended to show visitors to the UNESCO World Heritage Site how the inhabitants of the Proto-City once lived. The researchers burned wood and dung in the building, as was common practice 9,000 years ago. They used modern analysis methods to monitor air quality to investigate which pollutant values were created in the room air.
As the researchers report, extremely high levels of fine dust formed during the burning process, which go beyond all current limits. Even up to 40 minutes after the fire had burned out, the loads remained high, the analyzes showed. The fuel dung in particular ensured a fine dust concentration with peak values of up to 150,000 micrograms per cubic meter of air. According to the analyzes, a person’s position in relation to the fire played only a minor role in the overall exposure in the relatively small rooms.
“In Çatalhöyük, the lack of a real chimney and the fact that the buildings consisted of a single small room that united the living space and the fireplace means that everyone in the building was exposed to high levels of particulate matter from everyday domestic activities . The combination of an open fire and a lack of ventilation has certainly had a negative impact on the health of these people, ”Shillito sums up.
Sick from particulate matter?
The critical thing about fine dust is that the tiny particles not only get stuck in the lung tissue, but can also get into the bloodstream. As a result, they can also cause damage outside the respiratory system. This is precisely what is apparently also reflected in the findings on the remains of residents of Çatalhöyük, the researchers report: Many show signs of inflammation in the bone tissue. Chronic exposure to particulate matter could have caused this, write Shillito and her colleagues.
Finally, co-author Anil Namdeo from Northumbria University moves the past to the present: “Many people around the world still use biomass for cooking and heating in poorly ventilated houses. It is estimated that indoor air pollution could cause more than four million deaths each year. Our archaeological study now focuses on this problem in a special way, ”says the air quality management expert.
Source: Newcastle University, Article: Environmental Geochemistry and Health doi: 10/1007 / s10653-021-01000-2